1. Field of the Invention
The present invention relates to automated data collection systems that collect information from radio frequency identification (RFID) tags, and more particularly to an RFID system that allows access to RFID tags outside of the operable range of an RFID reader.
2. Description of the Related Art
In the automatic data identification industry, the use of RFID tags has grown in prominence as a way to track data regarding an object to which the RFID tag is affixed. An RFID transponder generally includes a semiconductor memory in which digital information may be stored, such as an electrically erasable, programmable read-only memory (EEPROM) or similar electronic memory device.
Since RFID tags do not include a radio transceiver, they can be manufactured in very small, lightweight and inexpensive units. RFID tags that extract their power from the interrogating field are particularly cost effective since they lack a power source. In view of these advantages, RFID tags can be used in many types of applications in which it is desirable to track information regarding a moving or inaccessible object. One such application is to affix RFID tags to packages or parcels moving along a conveyor belt. The RFID tags contain stored information regarding the packages, such as the originating or destination address, shipping requirements, pick-up date, contents of the package, etc. An RFID reader disposed adjacent to the conveyor belt can recover the stored information of each RFID tag as it passes on the conveyor belt. The RFID reader may then communicate the collected information to a computer or computer network for further processing by a software application.
Methods have been identified for using RFID tags to support passive interrogation and management of installed equipment configuration and status information. These passive techniques do not require the user to power up the installed units but do require an RF path between the interrogating equipment and the installed equipment. For equipment installed in aircraft this means that access ports/doors need to be opened to the Electronic Equipment (EE)-bay and other areas where the equipment is installed. To fully survey an airplane's configuration or fault status would require the ground crew to open multiple access ports and to spend considerable time and effort to read all airplane equipment tags. This approach also requires the airplane to be on the ground and precludes data collection during taxi or other flight phases. Similarly, access to RFID tags is unavailable while items are in metal storage or shipping containers. Opening the containers is not an option during shipment.
U.S. Pat. Publicn. 20050068179, entitled “Distributed RF Coupled System,” discloses an RFID sensor system that includes a conducting path having first and second conductors, and one or more RFID sensing transceivers spatially-distributed along the conducting path and capactively-coupled to the first and second conductors. The system further includes a controller that provides an AC signal on the conducting path, and receives signals from the one or more RFID sensing transceivers. The conducting path and RFID sensing transceivers can formed in a flexible substrate and mated together.
U.S. Pat. No. 6,212,401, issued Apr. 3, 2001, entitled “Data Acquisition Using Telephone Connection,” discloses a hand-held scanner that incorporates a cellular telephone module. The scanner communicates with a host which serves as a reading or data distribution device. This permits the use of a cableless scanner for low powered and secure wireless transmission. The scanner is able to take advantage of the existing design features of a local cellular network. One mode of operation allows the connection to be limited to an amount of time corresponding to that required for transferring of the data.
What is desired is an RFID system that efficiently allows access to RFID tags outside of the operable range of an RFID reader by providing the ability to interrogate inaccessible tags and transferring that data to a reader system.